L. A. Avinash Chunduri; Aditya Kurdekar; Bulagonda Eswarappa Pradeep; Mohan Kumar Haleyurgirisetty; Venkataramaniah K; Indira K. Hewlett
Abstract
Streptavidin labelled fluorescent ZnO nanoparticles have been surface engineered to develop a fluorescent ZnO nanoparticle linked immunoassay (FZLIA) for the sensitive detection of HIV infection. ZnO nanoparticles were synthesized by a single step chemical precipitation method. Cysteine was used to graft ...
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Streptavidin labelled fluorescent ZnO nanoparticles have been surface engineered to develop a fluorescent ZnO nanoparticle linked immunoassay (FZLIA) for the sensitive detection of HIV infection. ZnO nanoparticles were synthesized by a single step chemical precipitation method. Cysteine was used to graft carboxyl groups on to the surface of nanoparticles in a single step. Cysteine capped ZnO nanoparticles exhibited fluorescence at 546 nm when excited with 358 nm and FESEM confirmed the particle size to be 50-70 nm. FTIR and TGA confirmed the functionalisation of carboxyl groups by cysteine. The amount of cysteine grafted on the ZnO nanoparticles calculated as 68.1% from TGA analysis indicated the presence of large amount of carboxyl groups. ZnO nanoparticles were conjugated to streptavidin and the same were deployed as fluorescent probes in the development of the FZLIA platform for the early and accurate detection of HIV infection. The linear dose dependent detection range was from 25 pg/mL to 1000 pg/mL. HIV positive and HIV negative plasma samples were tested using FZLIA for the presence of HIV-1 p24 antigen. This immunoassay exhibited no false positive and false negative results with the clinical samples tested. This highly sensitive HIV-1 p24 antigen assay may be useful to improve blood safety by reducing the antibody negative window period in blood donors in resource limited settings where nucleic acid testing is not practical or feasible. This technology can be transferred to a lab-on-chip platform for use in resource limited settings and can also be easily adopted for the detection of other antigens.
Vijay Bhooshan Kumar; Pradip Paik
Abstract
In this work, we reported the control size and shape dependent cellular interactions of ZnO nanoparticles ranging from tiny nanodisks to nanorods, with carcinoma cells. These particles were synthesized through the wet chemical synthesis approach. Size and shape of the ZnO nanoparticles were tuned by ...
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In this work, we reported the control size and shape dependent cellular interactions of ZnO nanoparticles ranging from tiny nanodisks to nanorods, with carcinoma cells. These particles were synthesized through the wet chemical synthesis approach. Size and shape of the ZnO nanoparticles were tuned by varying the concentration of Igapal CO50. Size and shape dependent interactions were investigated with human carcinoma cells (K562, a Leukaemia Cancer Cells) without attaching any anticancer drugs and the results manifest that the size, shape and physical properties of ZnO nanoparticles are preferentially the critical factors in interactions and killing the cancer cells when no anticancer drugs were used. ZnO nanoparticles are used of aspect ratio from 1.3 to 5.5. Interaction and killing of carcinoma cells depend on the extent of defects and on the electro paramagnetic behavior of the ZnO nanoparticles. Further, Raman and EPR studies revealed that the size dependent phonon localization of oxygen defects of ZnO control the formation of singlet oxygen on interactions with cancer cells and regulate the anticancer effects of ZnO nanoparticles even in the absence of drugs. ZnO NPs with low aspect ratio is more vigorous in killing the carcinoma cells.
Aruna P. Wanninayake; Benjamin C. Church; Nidal Abu-Zahra
Abstract
Organic solar cells were fabricated with varying amounts of ZnO-NPs in a buffer layer located over an active layer of P3HT/PCBM incorporating a fixed amount of CuO nanoparticles. The buffer layer serves as an electron transporting layer in the device. Thermal annealing treatment was applied to all the ...
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Organic solar cells were fabricated with varying amounts of ZnO-NPs in a buffer layer located over an active layer of P3HT/PCBM incorporating a fixed amount of CuO nanoparticles. The buffer layer serves as an electron transporting layer in the device. Thermal annealing treatment was applied to all the devices at different temperatures (150 o C, 200 o C and 250 o C) to optimize the nanoscale morphology. The samples which were annealed at 200 o C exhibited the best power conversion performance. The enhanced morphological and optoelectronic properties attained by applying thermal annealing increased the power conversion efficiency by 14.6% compared to a reference cell. The ZnO-NPs buffer layer improved the exciton dissociation rate, electron mobility, optical absorption and charge collection at the anode, resulting in higher short circuit currents and external quantum efficiencies. The short circuit current (Jsc) of the optimum device was measured at 8.949 mA/cm 2 compared to 7.62 mA/cm 2 in the reference cell before annealing. Meanwhile, the external quantum efficiency (EQE) increased from 61.8% to 62.9%, after thermal annealing.
Mpho W. Maswanganye; Koena E. Rammutla; Thuto E. Mosuang; Bonex W. Mwakikunga; Sone T. Bertrand; Malik Maaza
Abstract
Co and In co-doped nanopowders of ZnO as well as In and Co singly doped ZnO were successfully prepared using sol-gel method. The synthesized samples were characterized using x-ray diffraction (XRD), UV-vis spectroscopy (UV-vis), Raman spectroscopy (RS), Transmission Electron Microscopy (TEM) and Energy ...
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Co and In co-doped nanopowders of ZnO as well as In and Co singly doped ZnO were successfully prepared using sol-gel method. The synthesized samples were characterized using x-ray diffraction (XRD), UV-vis spectroscopy (UV-vis), Raman spectroscopy (RS), Transmission Electron Microscopy (TEM) and Energy Dispersive Spectroscopy (EDS). The effects of In and Co co-doping on the structural and optical properties were investigated. XRD results showed no peaks associated with In 3+ or Co 2+ ions indicating that In 3+ and Co 2+ ions substituted for Zn 2+ ions in the ZnO wurtzite structure, this was corroborated by the EDS results. Doping ZnO nanoparticles with In and Co significantly reduced the grain sizes whereas the lattice parameters were not significantly affected. TEM results confirmed that the nanoparticles were spherically shaped. Raman spectroscopy also confirmed that the ZnO nanoparticles were of a wurtzite hexagonal structure. Single doping reduced the energy band gaps and co-doping reduced them even further.